I thought this might be of interest to GMC drivers.
On our recent 6400 mi trip in our 4104 I had a lot of oil on the rear engine cover, and I mean a lot of oil! I had to clean off the whole rear end all the way up to the window every time we stopped. After arriving home I discovered that the left airbox metal drain tube was missing the hose that the RH one had. This LH metal drain tube is only about 6" long at most.
After adding a hose on the left drain that went almost to the ground I had zero oil on the engine cover. I was amazed to say the least.
I decided that the oil dripping from the short metal tube was being picked up by the air flow up from the highway, then getting caught in the air blast from the radiator fan and being blown all over the engine and engine cover. The radiator fan is missing the outboard shroud. I understand this is pretty common with 4104s. It is also missing all the belly pans. This is no surprise because I have never seen a 4104 or 4106 with any belly pans left.
On our recent 64000 mi trip in our 4104
Gus,
That was one long trip......
Gus: If your airbox drains are dripping while you are driving, you should install the GM pressure sensitive valves in the drain tube. They close when the airbox pressure comes up.
Stan,
Good point, I just assumed they were blowing out an accumulation from idle time. I better check into that!
Gary,
My keyboard added an extra zero there!!
Gus: I don't know when GM came up with the valves for the airbox drains but it would certainly be after the 4104, as early 8V71 engines didn't have them. When RPM increases, airbox pressure rises and the valve should close. Any excess oil or fuel in the airbox then goes through the ports and becomes fuel instead of dripping on the road.
Gus,
Sorry but I had to do that. No disrespect intended. My backside was sore just thinking of that trip.
The 6400 miles was one great trip, one that I will attempt when retired.
Good Luck Gus,
Gary
Stan,
Now you have me wondering if I should add these valves since they weren't original equipment on my '54. I had read about them on the forum before but forgot about it but didn't know they weren't on older buses.
Do I have any opinions from others on this? I can't believe I just asked for opinions, the result will be my own fault!
Gary,
No disrespect received. I thought it was funny. Sore butt was a real concern on the trip but we made quite a few 3-7 day stops along the way and were gone from 25 Apr to 30 May so it wasn't too bad. I didn't drive more than 450 mi per day and quite a few days a lot less. It was a nice relaxing trip.
Gus, do you have the blow-by catch container installed to catch the oil being blown out. A couple of gallon containers tied up under the coach with the puke hoses installed in the opening really helps a lot. Also DD sells a package to accomplish this also.
Richard
Richard,
No, I don't have any kind of catch system yet. I spent so much time trying to get the oil spray stopped that the catch had to wait. I'm leaving on a 1200 mi trip tomorrow so will have a look when I return.
I looked at the jug method and couldn't figure out a good way to do it. My next effort is going to be toward the transverse PVC pipe with a bottom drain that someone else recommended.
Try it. You'll like it I guarantee!. Keep us updated.
Richard
Quote from: gus on June 26, 2007, 02:04:44 PM
Richard,
No, I don't have any kind of catch system yet. I spent so much time trying to get the oil spray stopped that the catch had to wait. I'm leaving on a 1200 mi trip tomorrow so will have a look when I return.
I looked at the jug method and couldn't figure out a good way to do it. My next effort is going to be toward the transverse PVC pipe with a bottom drain that someone else recommended.
Where are these tubes located and would 77 MCI 8 have them?
James,
If you have a DD I presume you have drain tubes. However, it is best left up to the MCI guys to answer this.
Richard,
I forgot to ask, what does the DD package look like?
Don't know. Just read about it. Heard it cost $150 so I made my own out of PVC. Someone posted a picture years ago on one of the boards.
Richard
Quote from: gus on June 26, 2007, 06:34:44 PM
Richard,
I forgot to ask, what does the DD package look like?